Love London? Sow some grass.

The starling is king in London's gardens, long live the king.

Our Big Garden Birdwatch results this year show no change in the top ten species. Starling is number one, followed by the house sparrow and woodpigeon. Fourth is the cheeky blue tit and fifth is the sonorous blackbird. Alarm bells are ringing though because the populations of our top two species are crashing around our ears. In fact, for the first time in our records the king has abandoned the City. Starlings didn't even make it on to the bird list for the City of London.

Admittedly the City is not the greenest of areas but last year starlings came in eighth place there, and the house sparrow was ranked thirteenth. This year the house sparrow is bottom of the list in twenty-second place and the king has abdicated.

So, what are we doing about it?

Three things:

1. we're harassing the London Mayoral candidates, asking then to adopt five key green RSPB pledges that would help;
2. we're offering free advice to anyone who has access to an outdoor space on what they can do to support wildlife;
3. we're spending £90,000 a year trying to establish the cause of the house sparrow's decline.

We already know that only 15% of starling juveniles survive beyond their first year and this is primarily due to a lack of their favourite food, earthworms and leather jackets (the larvae of daddy longlegs that were so common when I was but a lad). Addressing this means people changing the way they look after their lawns and being prepared to share this space with leather jackets.

Private gardens make up about a fifth of Greater London's total area. That's about 38,000 hectares. Compare that with the size of our fantastic reserve at Purfleet. Rainham Marshes [pictured right] presently covers some 350 hectares. It's packed full of wildlife, from water voles to lapwings. Imagine turning 38,000 hectares of land into wildlife friendly space and you'll see why private gardens are so important.

The demand for housing and development in London is HUGE. But, with a bit of thought, we can meet these needs and enjoy wildlife. Londoners can often be blunt so I'm now used to being asked "why?"

We're only now starting to fully understand what nature does for us. How trees and grassy areas absorb rain preventing flash floods, how trees and reedbeds absorb pollution, how nature balances our environment and keeps it ticking over. Trees can help reduce the air temperature by as much as 4 degrees. In our changing climate, they will become the best and cheapest air conditioners in the city! Birds and other wildlife all have a role in this. Added to this are the findings of new studies on the healing power of exposure to green spaces. Ministers are now seriously considering using NHS money to invest in gardens and parks as a means of therapy for physical and mental illness. This is based on a growing pool of evidence that the long-term benefits of giving people access to outdoor space far outweighs the cost of treatments for many modern ailments. Oh, and there's the good old fashioned response too; I like it and wildlife has as much right to be here as me.

So, let's put the grass back in London, and that's not a rallying call for free drugs before you add a pithy comment to this blog. Let's turn the city green with rye grass, wildflower meadows, fescues and clover. Go wild and plant a hedge, maybe a fruit tree so you can get fresh apples or pears to enjoy as you lie back in your deckchair to watch the birds flit backwards and forwards in what could well be the greenest, calmest, most beautiful and exciting city in the world.

Big Garden Birdwatch results for Greater London

1   Starling - averaging 3.14 per garden in our study but present in more than half the gardens surveyed.
2.  House sparrow - averaging 2.63 and in 46% of gardens.
3.  Wood pigeon - 2.38 average but in many gardens (77%).
4.  Blue tit - 2.09 compared with 2.4 in 2007 but present in 80% of gardens.
5.  Blackbird - territorial but doing well with an average of 1.72 and found in 85% of gardens.
6.  Feral pigeon - population holding steady at 1.41 and in a third of London gardens.
7.  Robin - a friendly bird in more than 80% of gardens but only averaging 1.23 in each garden.
8.  Magpie - 1.2 average and found in 57% of London gardens.
9.  Great tit - 1.07 average and in half the gardens surveyed.
10. Collared dove - found in about a third of gardens and averaging 0.9.

For more information on what YOU can do for wildlife, visit www.rspb.org.uk/hfw